共析珠光体钢在冷轧过程中的组织变化

用SEM、TEM及XRD等方法研究了共析钢中珠光体经40％-90％的冷轧变形后所产生的显微组织变化．接渗碳体形态特点,变形珠光体组织可分为以下3种类型：(1)不规则弯曲片层型,即变形后的渗碳体与轧制面呈大角度偏离且不规则弯曲的珠光体．(2)带有剪切带的粗大片层型,即被渗碳体剪切带分开且变形轻微的珠光体．(3)精细片层型,即与轧制方向平行排列、片间距细小且渗碳体严重变形的珠光体．精细片层区域的比例随着轧制压下率的提高而增大．此外,重度冷轧变形还引起渗碳体严重塑性变形和部分溶解．     

Investigation of Water Tree Degradation in Dry‐Cured and Extruded Three‐Layer (E‐E Type) 6.6‐kV Removed XLPE Cables

Dry‐cured and extruded three‐layer (E‐E type) 6.6‐kV cross‐linked polyethylene (XLPE) cables were introduced into electric power systems more than 30 years ago, but they do not experience failures because of water tree degradation. Also, the degradation index of water treeing for these cables has not been established. Therefore, investigating results of residual breakdown voltage and water tree degradation of these cables will help us plan for cable replacement and determine water tree degradation diagnosis scheduling, and will be fundamental data for cable lifetime evaluation. In this study, the authors measured the ac breakdown voltages of dry‐cured and E‐E type 6.6‐kV XLPE cables removed after 18 to 25 years of operation and observed the water trees in their XLPE insulation. As a result, it was observed that breakdown voltages were larger than the maximum operating voltage (6.9 kV) and the ac voltage for the dielectric withstanding test (10.3 kV). Water trees were mainly bow‐tie water trees and their maximum length was approximately 1 mm. Although the number of measured cables was limited, the lifetime of this type of cable was estimated to be approximately 40 years, even experiencing water immersion.     

Function symmetries and decoded-PLA realization

Decoded PLA (programmable logic array) has a distinct advantage over ordinary PLA, in that it can realize complex functions within a smaller chip area. This paper shows that decoded PLA is particularly suitable if the function to be realized has some form of symmetry. The paper describes a new approach for decoded PLA realizations using symmetries. It also describes a computer simulation which helps in the detection and use of such symmetries. Two such realizations are described.     

锰和硅添加对重度冷轧及退火后珠光体钢力学性能的影响

研究了几种锰、硅含量的Fe-0.8C合金在重度冷轧及退火后珠光体的显微组织变化及拉伸性能。结果表明,锰、硅的添加可使90%冷轧及450-650℃退火后共析珠光体的抗拉强度与屈服点均大幅度提高,但它们对冷轧珠光体延性的影响却是可以忽略的;与锰相比,硅的添加对冷轧及退火后珠光体钢延性的提高更有效,尤其当钢的强度较高时;锰、硅复合添加对重度冷轧及退火珠光体钢力学性能的提高也同样非常有效;经重度冷轧及低温(450℃)短时间退火,含硅或锰钢的抗拉强度和屈服点与冷轧态试样相比几乎没有下降,但其延性却明显提高;以硅、锰合金化的共析珠光体钢经90%冷轧及在450℃退火30-120s后强度-延性平衡达到最佳。     

Verification of USDA Home-Canning Recommendations for Tomatoes Processed at High Altitudes

Survivability of spoilage bacteria in tomatoes home-preserved at high altitude was studied. Thermal-processing followed USDA guidelines for two elevations (1540m and 2150m) and two process methods (boiling water-bath and pressure). Three treatments of Bacillus coagulans spores (no added spores, 10⁴ and 10⁵ spores/jar) were used. Processing method, elevation or inoculum level had no effect on post-processing count (P> 0.05), but over all treatment groups, surviving bacteria were found in 19.4% of the jars. Even though tomatoes processed up to 2150 m elevation were verified as safe, detectable surviving bacteria in some jars indicated processing guidelines were minimal.     

N-modular redundancy using the theory of error correcting codes

Using redundancy is basic to fault-tolerant computing. N-modular redundancy (NMR) is in some ways analogous to the use of a repetition code where an information symbol is replicated as parity symbols in a codeword. Linear error-correcting codes (ECC) use linear combinations of information symbols as parity symbols to generate syndromes for error patterns. In this paper, ECC theory has been applied to derive redundant circuits that tolerate faults in both the modules and checkers. Circuits using comparators for diagnosis are derived with a non-graph-theoretic approach. Coding theoretic principles are applied directly to NMR, so that extensive diagnosis of the fault-tolerant system is achieved.     

Positive-temperature-coefficient effect in conductive- ceramic/high-expansive-ceramic composites

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Microstructural Development in Partially Stabilized ZrO2 in the System CaO-ZrO2

The microstructures of 3 zirconias partially stabilized with CaO were investigated using scanning electron microscopy and qualitative and quantitative X-ray analysis. The structure was closely related to the heat treatments involved in fabrication. A bimodal structure with small grains of pure ZrO₂ dispersed along the grain boundaries of larger cubic solid-solution grains developed during slow cooling from 1850° to 1300°C. The presence of a liquid phase greatly enhances the growth of the pure ZrO₂ phase. An anneal at 1300°C induces precipitation of fine ZrO₂ particles within the solid-solution grains. The relative mechanical strengths of the materials are explained in terms of the weakening of the grain boundaries associated with the transformation of the grain-boundary phase on cooling.